oil temperature DODGE TRUCK 1993 Service User Guide

•

REAR
SUSPENSION
AND
AXLE
3 - 31
LUBRICANT

Hypoid gear lubricant, as defined by MIL-L-2105-B
and API GL 5 is the specified lube. MOPAR Hypoid
Gear Lubricant conforms with both of these specifica­
tions and is highly recommended.

CAUTION:
If a
rear
axle
is
submerged
in
water,
the

axle
lubricant
must
be
replaced
immediately,

DRAIN
AND
REFILL
(1) Drive the vehicle until the gear lubricant
reaches normal operating temperature. (2) Raise and support the vehicle. (3) Remove the lubricant fill hole plug from the
differential housing cover. (4) Remove the differential housing cover. Allow
the lubricant to completely drain from the housing and axle shaft tubes. (5) Flush the differential and the housing cavity
with a flushing oil to remove residual lubricant and
foreign matter. Do not use water,
steam,
kerosene
or
gasoline for
flushing,
(6) Scrape the residual gasket from the housing
and cover mating surfaces. Clean the mating sur­
faces with mineral spirits. Install a new cover gas­
ket. Apply a bead of MOPAR® Silicone Rubber Sealant on the housing cover (Fig. 2). Allow the seal­
ant to cure for a few minutes.
SEALING

SURFACE
CONTOUR
OF
BEAD
BEAD

THICKNESS

6.35mm
(1/4")
J9302-30

Fig.
2 Sealant On Housing Cower

Install
the
housing
cover
within 5
minutes
af­
ter
applying
the
sealant.
If not
installed,
the
sealant
must be
removed
and another
bead
ap­

plied.
(7) Install the cover on the differential. Install the
identification tag. Tighten the cover bolts to 47 Nem (35 ft. lbs.) torque.

CAUTION:
Overfilling
the differential" can
result
in

the
lubricant
foaming
and
overheating.

(8) Refill the differential housing with the speci­
fied quantity of MOPAR® Hypoid Gear Lubricant.
With Trac-Lok differentials, add a container of Trac-
Lok Lubricant additive.
(9) Install the fill hole plug. Tighten to 34 N-m (25
ft. lbs.) torque.
(10) Road test the vehicle. Drive the vehicle and
make 10 to 12 slow, figure-eight turns. This maneu­
ver will pump lubricant through clutch discs.

PINION
SHAFT
SEAL

REMOVAL
(1) Raise and support the vehicle.
(2) Mark the U-joint, pinion yoke, and pinion shaft
for reference.
(3) Disconnect the drive shaft from the pinion
yoke. Secure the drive shaft in an upright position to
prevent damage to the rear U-joint.
(4) Remove the pinion yoke nut and washer. Use
Remover C-452 and Wrench C-3281 to remove the
pinion yoke (Fig. 3).
(5) Mark the positions of the yoke and pinion gear
for installation alignment reference.
SPECIAL
TOOL

C-3281

SPECIAL
TOOL
C-452
J9102-31

Fig.
3 Pinion Yoke
Removal
(6) Use Remover C-748 to remove the pinion gear
seal (Fig. 4).

INSTALLATION
(1) Apply a light coating of gear lubricant on the
lip of pinion seal. Install the new seal (Fig. 5);
• Model 60 use Installer C-3719-A and Handle C-4735
• Model 70 use Installer C-359 and Handle C-4735 (2) Align the installation reference marks and po-

7 - 2
COOLING
SYSTEM

•

NOTE: HEATER
COOLANT FLOW
CIRCUIT
IS
ALWAYS

OPEN
EXCEPT
WHEN
IN MAX. A/C
OR
OFF
MODES
HEATER
INTAKE MANIFOLD
COOLANT FLOW "METERED" FROM REAR
TO

FRONT
AND
BELOW EXHAUST HEAT
CROSSOVER
SHUT
OFF
VALVE

A/C
ONLY COOLANT FLOW
-
PUMP
TO

CYLINDER
BLOCK,
UP
THROUGH
CYLINDER
HEADS
TO
INTAKE MANIFOLD WATER BOX
TO
RADIATOR
—
TO PUMP

•BYPASS
THERMOSTAT CLOSED-HIGH FLOW
THERMOSTAT OPEN
-
LOW FLOW

CYLINDER
HEAD
RR07B52

Fig.
2
Cooling
System
Routing—5.9L (V-8 Gas)—Typical All vehicles are equipped with either a 3.9L (V-6),
a 5.2L (V-8), a 5.9L (LDC-gas V-8), a 5.9L (HDC-gas
V-8) or a 5.9L (in-line 6 cylinder diesel) engine.
As coolant temperature reaches approximately

220°F,
the engine idle speed is increased by the pow-
ertrain control module (PCM) to provide increased
cooling system performance. The PCM was formerly
referred to as the engine controller or SBEC.

COOLING
SYSTEM
COMPONENTS—EXCEPT

DIESEL
ENGINE
The cooling system consists of:
• A down-flow radiator
• Thermal viscous fan drive
• Fan shroud
• Radiator pressure cap
• Thermostat
• Coolant reserve/overflow system
• Transmission oil cooler (automatic transmission)
• Coolant
• Water pump (to circulate coolant)
• Hoses and hose clamps Coolant flow circuits for 3.9L (V-6) and 5.2L (V-8)
engines with water cooled intake manifolds are
shown in figure 1. Coolant flow circuits for 5.9L (V-8 Gas) engines
with water cooled intake manifolds are shown in fig­ ure 2.
COOLING
SYSTEM
COMPONENTS-DIESEL

ENGINE
Coolant flow circuits for 5.9L (diesel) engines with
water cooled intake manifolds are shown in figure 3. The cooling system (Fig. 3) consists of: a cross-flow
radiator, engine driven cooling fan, thermal viscous
fan drive, fan shroud, radiator pressure cap, thermo­ stat, coolant reserve/overflow system, transmission
oil cooler (if equipped with an automatic transmis­
sion),
coolant, water pump, hoses and hose clamps.

SYSTEM
COOLANT ROUTING-DIESEL ENGINE
Coolant is drawn from radiator into the water
pump. Water pump output is directed to the engine oil cooler cavity of the cylinder block (Fig. 4). From the oil cooler cavity, the coolant circulates
around each cylinder. It then crosses to the lift pump
side of engine where it flows up into cylinder head
through openings in top of cylinder block (Fig. 4). Coolant flows past the valve bridges (Fig. 5), to ex­
haust manifold side of engine, to thermostat. As cool­ ant flows toward the thermostat, it provides cooling
for the injector nozzle.
When thermostat is closed (engine is below operating
temperature), coolant flows through bypass passage to
water pump inlet (Fig. 6). Once operating temperature is reached, the thermostat opens and blocks the bypass
passage. Coolant then flows to the radiator inlet.

•
COOLING
SYSTEM
7 - 6 COOLING SYSTEM DIAGNOSIS (EXCEPT DIESEL)

CONDITION
AND
CHICK

OPTIONAL
M°¥
GAUGE
READS
LOW
(!) Verify
gauge
reading. Is a low temperature indicated?
(2) Is code 17 recorded in On Board
Diagnostics
memory?
(3) Is the
gauge
reading in the cold
range?

(4) Low coolant level during cold ambient temperatures
(accompanied
with poor heater performance).
(5) Coolant level is correct.

GAUGE
HEADING
HIGH.
NO
PRESSURE
BLOW
OFF
FROM
RADIATOR
PRESSURE
CAP
OR
STEAM
FROM
COOLANT

RESERVE
TANK.

(1) Verify
gauge
reading. Is a high temperature reading indicated?
(2)
Gauge
reading at
"H"
without
signs
of boiling.
(3) Low coolant level in radiator and coolant reserve tank.
(4) Coolant level in radiator is low. But not low in coolant reserve tank.
(5) Test coolant
freeze
point.
(6) Ensure proper coolant flow.
DIAGNOSIS

30° TO 40°

GAUGE
TRAVEL
IS
NORMAL

Normal
Gauge
Travel
(1) Inspect temperature
gauge
sending
unit. Refer to Group 8, Electrical. Repair or replace sending unit as necessary.
(2) If code 17 is recorded, replace the thermostat. If not, the thermostat is not the
cause
of the low
gauge
reading.
(3) Inspect for
disconnected
sending
unit electrical connector or incorrect
sending
unit. Ensure that
gauge
sending
unit is installed

and
not an indicator light switch.
(4)
WARNING:
DO NOT
REMOVE
THE
RADIATOR
CAP
OF A
HOT,
PRESSURIZED
ENGINE.
SERIOUS
INJURY
CAN

RESULT
FROM
SCALDING
COOLANT.

Inspect
coolant level in the coolant reserve tank and radiator.

Inspect
system
for leaks.
(5) Inspect heater door
controls.
Refer to Group 24, Heating and
Air
Conditioning.

TO
TOP
AMBIENT

High
Gauge
Reading
— Hot Weather — Heavy Load
(1) Compare
gauge
reading to
High
Gauge
Reading Illustration
above.

(2) Inspect for grounded
gauge,
sending
unit or circuit. Refer to
Group
8, Electrical.
(3) a — Pill to full.
b
— Inspect for leaks in
system
and repair as
necessary,

c
—
Ensure
radiator pressure cap was shut tight. Verify
proper
operation of the radiator cap upper and lower
seals.

(4) a —
Fill
to full,
b
— Inspect for leaks in the
system
and repair as
necessary,

c
— Inspect for leaks in the coolant reserve tank to radiator
hose.

d
— Verify proper operation of the radiator cap upper and lower
seals.

(5) a — Adjust coolant solution to
50/50
mixture of anti-freeze and water. Refer to Coolant in this
group,

b
— If a reading is not recorded or below
—
50, the mixture is
too
rich. Clean
system
and
fill
with a
50/50
mixture of
anti-freeze and water. Refer to Coolant in this
group.

(6) a •— With the thermostat open and a slight amount of coolant
removed,
inspect for coolant flow through the radiator at
the
filler
neck opening,

b
— Determine reason for lack of coolant flow and repair as
necessary.
J9007-69

•

COOLING
SYSTEM
7 - 7 COOLING SYSTEM DIAGNOSIS (EXCEPT DIESELJ-GONTINUED

CONDITION
AND
CHECKS
DIAGNOSIS

TEMPERATURE
GAUGE
IS
INCONSISTENT,
CYCLES
AND/OR
IS
ERRATIC.

(1) Is cycle normal.
MID

(a)
Normal Gauge Reaction to Thermostat Cycle.

MID

(b) Normal Gauge Reaction at Stop After Heavy Use.
(c) Hot Water Build-Up is Normal at
Stop
after
Heavy Use.
(2)
Is
coolant in radiator low (air
will
build up in the cooling
system
(2)
Fill
system,
vent trapped air and check for leaks,
and
cause
the thermostat to open
late).

(3)
Is
a cylinder head gasket leak allowing exhaust
gas
to
enter
(3) a — Test for leaking cylinder head
gasket
leak
with
a
cooling
system
(exhaust
gas
building up in the cooling
system
will
commercially available Block Leak Tester,

cause
the thermostat to open
late).

b
— Check for coolant in engine oil.

c
— Inspect for
white
steam from exhaust
system.

(4)
Water pump impeller loose on shaft.
Loose
accessory
drive belt. (4) Repair or replace as necessary.

(5)
Air leak
on
the
suction
side of the
water
pump (allows air to build (5) Find leak and repair,
up
in cooling
system
causing
thermostat to open
late).

WARNING
LIGHT
GLOWS
ALL
THE
TIME
(VEHICLE
NOT
EQUIPPED
WITH
GAUGE).

(1) Inspect
temperature
gauge
sending
unit. The warning light
sending
(1)
Ensure
that
a warning light
sending
unit
is
installed, unit
has
a screwdriver slot in the electrode (used for calibration).

Gauge
sending
units do not have a slot in the electrode.

NO
GAUGE
READING
INITIALLY
THEN
HOT
INDICATION

(VEHICLE
EQUIPPED
WITH
GAUGE).

(1)
Gauge
stationary
until
very hot, then
moves
immediately to "H"
(1)
Vehicle
is
equipped
with
sending
unit for light not
gauge.
J9007-70

7-10 COOLING SYSTEM
•
DIESEL
COOLING SYSTEM
DIAGNOSIS

CONDITION AND CHECKS
DIAGNOSIS

OPTIONAL
60»F
GAUGE
READS
LOW 30° TO 40°
GAUGE
TRAVEL
IS
NORMAL
(1)
Verify
gauge reading. Is a low
temperature
indicated?
(2) Thermostat stuck in open position?
(3) Is the gauge reading in the cold range?
(4) Low coolant
level
during cold ambient temperatures (accom­ panied
with
poor
heater
performance).
(5) Coolant
level
is correct.
MID

Normal
Gauge
Travel

(1) Inspect
temperature
gauge sending unit. Refer to Group 8,
Electrical. Repair or replace sending
unit
as necessary.
(2) If
Yes,
replace the thermostat. If not, the thermostat is not the
cause
of the low gauge
reading.

(3) Inspect for disconnected sending
unit
electrical
connector or
incorrect
sending unit. Ensure
that
gauge sending
unit
is in­
stalled and not an indicator light switch.
(4) WARNING: DO NOT REMOVE THE RADIATOR CAP
OF
A HOT, PRESSURIZED ENGINE. SERIOUS IN­
JURY CAN RESULT FROM SCALDING COOLANT. Inspect coolant
level
in the coolant reserve tank and radiator. Inspect system for leaks.
(5) Inspect
heater
door
controls.
Refer to Group 24, Heating and
Air Conditioning.

GAUGE
READING HIGH. NO PRESSURE BLOW OFF FROM RADIATOR PRESSURE CAP OR STEAM FROM
COOLANT
RESERVE
TANK.
X

(1)
Verify
gauge reading. Is a high
temperature
reading indi­
cated?

(2) Gauge reading at "H"
without
signs
of boiling.
(3) Low coolant
level
in radiator and coolant reserve tank.
MAXIMUM
HOT

WEATHER

HEAVY
LOAD

MAXIMUM
UP

TO
TOP AMBIENT High Gauge
Reading
— Hot
Weather
—
Heavy
Load

(1) Compare gauge reading to High Gauge Reading Illustration
above.
(2) Inspect for grounded
gauge,
sending
unit
or circuit. Refer to

Group
8, Electrical.
(4) Coolant
level
in radiator
is
low.
But
not low in coolant reserve tank.
(5) Test coolant
freeze
point. (3) a-
b — (4) a-
b —
d —
(5) a- (6) Ensure proper coolant flow.
(6) a-
b —
Fill
to
full.

Inspect for leaks in system and
repair

as
necessary.
Ensure
radiator pressure cap was shut
tight.
Verify
proper operation of the radiator

cap
upper and lower
seals.
Fill
to
full.

Inspect for leaks in the system and
repair

as
necessary.
Inspect for leaks in the coolant reserve
tank to radiator hose.
Verify
proper operation of the radiator cap
upper and lower
seals.

Adjust coolant solution to
50/50
mixture
of
anti-freeze
and
water.
Refer to Coolant
in this group. If a reading is not recorded or below - 50.
the
mixture
is too rich. Clean system and
fill

with
a
50/50
mixture
of
anti-freeze
and
water.
Refer to Coolant in this group.
With the thermostat open and a slight amount
of coolant removed, inspect for coolant flow
through the radiator at the
filler
neck opening. Determine reason for lack of coolant flow
and
repair
as necessary.
J9107-22

7
- 12
COOLING
SYSTEM

• DIESEL COOLING SYSTEM DIAGNOSIS-CONTINUED

CONDITION
AND
CHECKS
DIAGNOSIS

TEMPERATURE GAUGE
IS
INCONSISTENT,
CYCLES
AND/OR
IS
ERRATIC.
J
(1)
Is
cycle
normal.

(a)
Normal
Gauge
Reaction
to Thermostat
Cycle.
Normal
Gauge
Reaction
to Thermostat
Cycle.

MID

(b)
Normal
Gauge
Reaction
at
Stop
After
Heavy
Use.
(c)
Hot
Water
Build-Up
Is
Normal
at
Stop
after
Heavy

Use.

(2)
Is
coolant
in
radiator
low
(air
will
build
up in
the
cooling
system and cause
the
thermostat
to
open
late). (2)

Fill
system,
vent
trapped
air
and
check
for
leaks.

(3)
Is
a
cylinder
head
gasket
leak
allowing
exhaust
gas
to
enter
cooling
system
(exhaust
gas
building
up in
the

cooling
system
will
cause
the
thermostat
to
open
late).
(3)

a
—
Test
for
leaking
cylinder
gasket
leak
with
a

commercially
available
Block
Leak
Tester,

b
—
Check
for
coolant
in
enaine
oil.

c
—
Inspect
for
white
steam
from
exhaust
system.

(4)
Water
pump
impeller
loose
on
shaft.
Loose
accessory
drive
belt. (4)

Repair or
replace
as
necessary.

(5)
Air
leak
on
the
suction
side
of the
water
pump
(allows
air
to
build
up in
cooling
system causing
thermostat
to
open
late). (5)

Find
leak
and
repair.

PRESSURE
CAP
VENTS
TO
ATMOSPHERE
AND
COOL­

ANT
RESERVE
TANK.
TEMPERATURE GAUGE
READ­

ING ABOVE NORMAL
BUT NOT
HIGH.

(1)
Test
radiator
pressure
cap
relief
pressure.
Refer
to
Radiator
Pressure
cap
section
in
this
group.
ID

Replace
cap
if relief
pressure
is
lower
than
14
psi.
COOLANT
LOSS
VISIBLE
ON
GROUND BELOW VEHI­

CLE,
BUT NO
PRESSURE
CAP
BLOW
OFF.

(1)
Inspect
system
for
leaks.
(1)
Repair
as
necessary.
J9107-23

•

COOLING
SYSTEM
7 - 27 down to -67.7°C (-90°F). A higher percentage will
freeze at a warmer temperature. Also, a higher per­ centage of antifreeze can cause the engine to over­
heat because specific heat of antifreeze is lower than
that of water.

CAUTION:
Richer
antifreeze
mixtures
cannot
be
measured
with
normal
field
equipment
and can

cause
problems
associated
with 100
percent
ethyl­

ene-glycol.

COOLANT SELECTION-ADDITIVES The presence of aluminum components in the cool­
ing system requires strict corrosion protection. Main­
tain coolant at specified level with a mixture of ethylene-glycol based antifreeze and water. Only use an antifreeze containing ALUGARD 340-2
™
such as
Mopar Antifreeze. If coolant becomes contaminated
or looses color, drain and flush cooling system and
fill with correctly mixed solution.
A 0.25 percent emulsifiable oil is added to the ra­
diator at the factory to prevent solder corrosion.

CAUTION:
Do not use
coolant
additives
that are

claimed
to
improve
engine
cooling.

COOLANT SERVICE-EXCEPT DIESEL It is recommended that the cooling system be
drained and flushed at 84,000 kilometers (52,500
miles) or 3 years, whichever occurs first. Then every
two years or 48,000 kilometers (30,000 miles), which­ ever occurs first.
COOLANT SERVICE-DIESEL ENGINE It is recommended that the cooling system be
drained and flushed every 24 months or 38,600 kilo­ meters (24,000 miles), whichever occurs first.
COOLANT LEVEL CHECK-ROUTINE Do not remove radiator cap for routine coolant
level inspections. The coolant level can be checked at the coolant reserve/overflow tank.
The coolant reserve/overflow system provides a
quick visual method for determining the coolant
level without removing the radiator pressure cap.
With engine idling and at normal operating temper­ ature, observe coolant level in coolant reserve/over­
flow tank. The coolant level should be between the MIN and MAX (diesel engine) or ADD and FULL (gas engines) marks.
ADDING ADDITIONAL COOLANT-ROUTINE Do not remove the radiator cap to add coolant
to the system. When adding coolant to maintain the correct level, do so at the coolant reserve/overflow
tank with a 50/50 mixture of ethylene-glycol anti­
freeze (containing Alugard 340-2 ™) and water. Re­ move the radiator cap only for testing or when
refilling the system after service. Removing cap un­ necessarily can cause loss of coolant and allow air to
enter system. This produces corrosion.
COOLANT LEVEL CHECK-SERVICE The cooling system is closed and designed to main­
tain coolant level to the top of the radiator.

WARNING:
DO
NOT OPEN RADIATOR DRAINCOCK

WITH
ENGINE RUNNING
OR
WHILE ENGINE
IS HOT

AND COOLING
SYSTEM
IS
UNDER
PRESSURE.
When vehicle servicing requires a coolant level
check in the radiator, drain several ounces of coolant
from the radiator drain cock. Do this while observing
the coolant reserve/overflow system tank. The cool­ ant level in the reserve/overflow tank should drop
slightly. If not, inspect for a leak between radiator and coolant reserve/overflow system connection. Re­
move radiator cap. The coolant level should be to the
top of the radiator. If not and if coolant level in re­ serve/overflow tank is at the ADD (gas engines) or
MIN (5.9L diesel engine) mark, check for:
• An air leak in the coolant reserve/overflow tank
• An air leak in the radiator filler neck
• Leak in the pressure cap seal to the radiator filler
neck
LOW COOLANT LEVEL-AERATION If the coolant level in the radiator drops below the
top of the radiator core tubes, air will enter the sys­
tem. Low coolant level can cause the thermostat pellet
to be suspended in air instead of coolant. This will cause the thermostat to open later, which in turn causes higher coolant temperature. Air trapped in
cooling system also reduces the amount of coolant
circulating in the heater core. This may result in low
heat output.
DEAERATION As the engine operates, air trapped in the cooling
system gathers under the radiator cap. The next time
engine is operated, thermal expansion of coolant will
push trapped air past radiator cap into coolant re­ serve/overflow tank. Here it escapes to atmosphere in
the tank. When engine cools down the coolant, it will
be drawn from reserve/overflow tank into radiator to replace removed air.

DRAINING
COOLING
SYSTEM

WARNING:
DO NOT
REMOVE
THE
CYLINDER BLOCK DRAIN PLUGS
OR
LOOSEN THE RADIATOR
DRAIN PLUG
WITH
SYSTEM
HOT AND
UNDER

PRESSURE.
SERIOUS BURNS
FROM
COOLANT
CAN OCCUR.

7 - 28
COOLING SYSTEM

DO NOT WASTE reusable coolant. If the solution
is clean, drain the coolant into a clean container for
reuse.
(1) Start the engine and place the heater control
temperature selector in the Full On position. Engine vacuum is needed to actuate the heater controls.
(2) Turn the ignition off. (3) Do not remove radiator cap when draining cool­
ant from reserve/overflow tank. Open radiator drain
plug and when tank is empty, remove radiator cap. If
the coolant reserve/overflow tank does not drain, re­ fer to the Testing Cooling System for Leaks section
in this group. The coolant need not be removed from
tank unless the system is being refilled with fresh mixture.
(4) On vehicles equipped with gas powered en­

gines,
remove the cylinder block drain plugs. These are located on the sides of the block towards the
front of engine, just above the oil pan (Fig. 36).

Fig.
36 Drain Plugs—Gas Powered
Engines—Typical

(5) Remove radiator pressure cap.

REFILLING
THE
COOLING SYSTEM
Clean cooling system prior to refilling. Refer to
Cooling System Cleaning section of this group. (1) Install the cylinder block drain plugs (Fig. 36).
(2)
Close radiator drain plug.
(3) Fill the cooling system with a 50/50 mixture of
water and antifreeze. (4) Fill coolant reserve/overflow tank to the MAX
(5.9L diesel engine) or FULL (gas engines) mark. (5) Start and operate engine until thermostat
opens. Upper radiator hose should be warm to touch. (6) If necessary, add 50/50 water and antifreeze
mixture to the coolant reserve/overflow tank to main­
tain coolant level. This level should be between the MAX and MIN (5.9L diesel engine) or ADD and FULL (gas engines) marks. The level in the reserve/ overflow tank may drop below the MIN (or ADD)
mark after three or four warm-up and cool-down cy­

cles.

COOLING SYSTEM CLEANING/REVERSE FLUSHING
CLEMMING Drain cooling system and refill with water. Run
engine with radiator cap installed until upper radia­
tor hose is hot. Stop engine and drain water from system. If water is dirty, fill system with water, run
engine and drain system. Repeat until water drains
clean.

REVERSE
FLUSHING
Reverse flushing of cooling system is the forcing of
water through the cooling system. This is done using air pressure in the opposite direction of normal cool­
ant flow. It is usually only necessary with very dirty
systems with evidence of partial plugging.

REVERSE
FLUSHING
RADIATOR Disconnect radiator hoses from radiator inlet and
outlet. Attach a section of radiator hose to radiator
bottom outlet fitting and insert flushing gun. Con­
nect a water supply hose and air supply hose to flushing gun.

CAUTION:
Internal
radiator
pressure must
not'ex­

ceed 138 kPa (20 psi) as damage to
radiator
may re­
sult

Allow radiator to fill with water. When radiator is
filled, apply air in short blasts. Allow radiator to re­
fill between blasts. Continue this reverse flushing
until clean water flows out through rear of radiator cooling tube passages. Have radiator cleaned more extensively by a radiator repair shop.

REVERSE
FLUSHING
ENGINE-EXCEPT DIESEL Drain cooling system. Remove thermostat housing
and thermostat. Install thermostat housing. Discon­
nect radiator upper hose from radiator and attach
flushing gun to hose. Disconnect radiator lower hose
from water pump and attach a lead-away hose to wa­
ter pump inlet fitting.

CAUTION;
On vehicles equipped
with
a
heater
water

control
valve, be sure
heater
control
valve is closed

(heat
off). This
will
prevent
coolant
flow
with
scale

and
other
deposits
from
entering
heater
core.
Connect water supply hose and air supply hose to
flushing gun. Allow engine to fill with water. When engine is filled, apply air in short blasts, allowing system to fill between air blasts. Continue until
clean water flows through the lead away hose.

•

COOLING
SYSTEM
7 - 31 It utilizes thermal expansion and contraction of cool­
ant to keep coolant free of trapped air. It provides a
volume for expansion and contraction of coolant. It
also provides a convenient and safe method for
checking coolant level and adjusting level at atmo­
spheric pressure. This is done without removing ra­
diator pressure cap. It also provides some reserve
coolant to cover minor leaks and evaporation or boil­
ing losses.
FAN

SHROUD
J9107-67

Fig.
40 Coolant Reserve/Overflow Tank—Gas
Engines
Fig.
41 Coolant Reserve/Overflow Tank—Diesel
Engines

Refer to Coolant Level Check—Service, Deaeration
and Radiator Pressure Cap sections in this group for
coolant reserve/overflow system operation and ser­

vice.
Should the reserve/overflow tank become coated
with corrosion or emulsifiable oil, it can be cleaned
with detergent and water. Rinse tank thoroughly be­
fore refilling cooling system as described in the Cool­ ant section of this group.

TANK REMOVAL
(1) Remove overflow hose at reserve/overflow tank.
(2) Unsnap the coolant reserve/overflow tank from
fan shroud. Lift straight up. The fan shroud is
equipped with T-shaped slots to attach the tank.

TANK INSTALLATION
(1) Snap tank into fan shroud.
(2) Install overflow hose to tank.

RADIATOR
PRESSURE
CAP
Radiators are equipped with a pressure cap, which
releases pressure at some point within a range of 97- 124 kPa (14-18 psi). The pressure relief point (in
pounds) is engraved on top of cap. The cooling system will operate at pressures
slightly above atmospheric pressure. This results in a
higher coolant boiling point allowing increased radi­ ator cooling capacity. The cap (Fig. 42) contains a
spring-loaded pressure relief valve that opens when
system pressure reaches release range of 97-124 kPa (14-18 psi).

Fig.
42 Radiator
Pressure
Cap and
Filler
Neck—Typical
A vent valve in the center of cap allows a small
coolant flow through cap when coolant is below boil­
ing temperature. The valve is completely closed
when boiling point is reached. As the coolant cools, it contracts and creates a vacuum in the cooling sys­
tem. This causes the vacuum valve to open and cool­ ant in the reserve/overflow tank to be drawn through
its connecting hose into radiator. If the vacuum valve
is stuck shut, the radiator hoses will collapse on cool-
down. Clean the vent valve (Fig. 42).
A rubber gasket seals radiator filler neck to pre­
vent leakage. This is done to keep system under

•

COOLING
SYSTEM
7 - 33 The radiator supplies sufficient heat transfer to
cool the engine and automatic transmission (if equipped).

RADIATOR COOLANT FLOW CHECK
Use the following procedure to determine if coolant
is flowing through the cooling system.
(1) Idle engine until operating temperature is
reached. If the upper radiator hose is warm to the
touch, the thermostat is opening and coolant is flow­ ing to the radiator.

WARNING:
HOT,
PRESSURIZED COOLANT
CAN
CAUSE
INJURY
BY
SCALDING. USING
A
RAG
TO

COVER
THE
RADIATOR
PRESSURE
CAP,
OPEN RADIATOR
CAP
SLOWLY
TO THE
FIRST STOP.
THIS
WILL
ALLOW
ANY
BUILT-UP
PRESSURE
TO
VENT
TO
THE
RESERVE/OVERFLOW TANK. AFTER
PRESSURE
BUILD-UP
HAS
BEEN RELEASED,
RE­

MOVE
CAP
FROM FILLER NECK.

(2) Drain a small amount of coolant from the radi­
ator until the ends of the radiator tubes are visible
through the filler neck. Idle the engine at normal op­
erating temperature. If coolant is flowing past the
exposed tubes, the coolant is circulating.

RADIATOR REMOVAL-EXCEPT DIESEL
(1) Disconnect negative battery cable from battery.

WARNING;
DO NOT
REMOVE
THE
CYLINDER BLOCK DRAIN PLUGS
OR
LOOSEN
THE
RADIATOR
DRAINCOCK
WITH
THE
SYSTEM
HOT AND
UNDER
PRESSURE.
SERIOUS BURNS FROM COOLANT
CAN OCCUR.

(2) Drain the cooling system. Refer to Draining
Cooling System.
(3) Disconnect throttle cable from clip at radiator
fan shroud. (4) Remove hose clamps and hoses from radiator.
Special Clamp Tool number 6094 (Fig. 44) may be
used to remove the constant tension clamps.
(5) Remove coolant reserve/overflow tank hose
from radiator filler neck nipple.
(6) If equipped with an automatic transmission
(except diesel), disconnect oil cooler hoses at radiator
lower tank.
(7) Remove fan shroud mounting bolts/clips and
position shroud rearward on engine (Fig. 45). (8) Loosen radiator lower mounting bolts. Remove
the upper mounting bolts. Lift radiator straight up and out of engine compartment. Take care not to
damage radiator cooling fins or tubes.

INSTALLATION
(1) Position shroud rearward on engine.
(2) Slide radiator into position. Place behind radi­
ator support with lower mounting holes (slots) rest-
HOSE
CLAMP
TOOL
6094
HOSE

CLAMP

J9207-36

Fig.
44
Hose
Clamp
Tool
RADIATOR SHROUD
MOUNTING MOUNTING
BOLTS
CUPS
RADIATOR
V1

FAN SHROUD^
J9207-44
Fig.
45 Radiator and Fan
Shroud—Gas Engines

ing on loosened bottom mounting bolts. Install upper
mounting bolts. Tighten all mounting bolts to 11
N*m (95 in. lbs.) torque.
(3) Connect radiator hoses.
(4) Connect transmission oil cooler lines to bottom
tank. Tighten hose clamps to 4 N#m (35 in. lbs.)
torque.
(5) Position fan shroud on radiator flange. Install
mounting clips (Fig. 45).
(6) Connect throttle cable to fan shroud.
(7) Position heater controls to full heat position.
(8) Fill cooling system with coolant. Refer to Refill­
ing Cooling System in this group.
(9) Operate engine until it reaches normal temper­
ature. Check cooling system and automatic transmis­
sion (if equipped) fluid levels.

RADIATOR REMOVAL-DIESEL
(1) Disconnect negative battery cable from battery.